On Wednesday, the American Heart Association announced something that those of us who’d been reading the medical literature carefully had known for a while: Bad gums do not cause heart disease.
Periodontitis is linked to bad heart disease, you see, as studies have shown, and periodontists have sure been using this as an excuse to tell us to floss. But there’s never been a convincing study showing that one causes the other.
In fact, it’s not even clear how you’d do that study. “Let’s see, for a control group, we should have 100 people convince themselves they’re flossing for a year, but not actually floss….oh, what else can we get funding for?”
That “news” prompted an email from Retraction Watch friend Marc Abrahams, who noted that a study called “Periodontitis and Cardiovascular Disease: Floss and Reduce a Potential Risk Factor for CVD” had been retracted from Angiology last year.
The retraction notice — which will cost you $32 to read — consists of this highly informative sentence:
The publisher and the editor have retracted the article from the issue.
The abstract is all that we could find online:
There is evidence supporting an association between cardiovascular disease (CVD) and periodontitis. We determined whether patients with chronic periodontitis, who are otherwise healthy individuals, have higher serum concentrations of emerging risk markers of CVD such as C-reactive protein (CRP) and interleukin 6 (IL-6) and investigated the effect of subsequent periodontal treatment on the levels of these markers. A total of 40 individuals were included in the study. Serum levels of CRP and IL-6 were estimated twice, once on the initial visits and the other 3 months after periodontal therapy. The mean CRP and IL-6 levels were significantly higher (P < .001) in the patients compared with controls and significantly decreased (P < .001) following periodontal treatment. This study suggests that periodontitis is a potential modifiable risk factor for CVD.
The study has been cited twice, according to Thomson Scientific’s Web of Knowledge — and was not cited in the American Heart Association’s statement in Circulation.
We’ve tried to contact the editor of the journal, and the corresponding author, for more details.
In the meantime, we may have one clue about why the paper was retracted: A December 6, 2010 version has eight authors, while a June 13, 2010 version has only two. That doesn’t necessarily mean anything, but authorship disputes can certainly lead to problems.
Update, 3:30 p.m. Eastern, 4/21/12: Turns out we were right; the retraction happened because of a disagreement over authorship. Angiology editor D.P. Mikhailidis tells Retraction Watch:
I was not involved in that particular retraction process. However, I have been informed that this was the result of a dispute between the authors regarding authorship. In my opinion, it is unfortunate that this dispute could not have been resolved by the authors agreeing on an erratum statement.
Oh dear, just as I thought maybe cleaning my teeth for once would extend my lifespan, somebody throws a spanner in the works.
RE: the retraction notice
Gee, for $ 32 I could buy a bottle of whisky, or 4 bottles red wine, or 24 bottles beer, either of which will bring me more utility and, should I consume it moderately, will reduce my risk for CVD more than flossing would.
Dear Colleagues in Science:
Read the article critically. It is not a scientific paper. Remember, the American Heart Association is a public relations organization that sells its endorsements for as much as $700,000.
Let us not follow political/business/public relations organization pronouncements in lock step GroupThink.
Let us not jump to impetuous decisions without investigating the evidence CRITICALLY. If you read the “position paper” critically you’ll see that the review builds a straw man. No serious investigator really contends that periodontitis is a sine qua non for heart attacks.
Moreover, the conclusion is a non sequitur. Both atherosclerotic cariovascular diseases and periodontitis syndromes manifest multi-factorial etiologies. So the implication that singular cause relationships can be drawn is fallacious reasoning. Speak of “risk factors” in a multi-factorial flux and periodontitis emerges as a provocative “black swan”.
Single causal and dichotomous reasoning lead to such discordant conclusions as: “Tuberculosis is not caused by germs; I know a man who was exposed to it and did not develop TB.”
or
HIgh fat diets and elevated cholesterol don’t “cause” heart attacks; I know of many cases where octogenarians died of cancer and had no heart attacks despite the fact that they had both so-called “risk factors”.
In this postmodern world where truth is emerging as an individual existential “right” not a universal empirical imperative, clear reasoning and prudent thought will serve us all quite well if we can tolerate the self-discipline it demands.
Quo Vadis?
— ncm